The present invention disclosed herein relates to a frequency tunable terahertz transceiver and a method of manufacturing a dual wavelength laser.
A terahertz band (i.e., 0.1 THz to 3 THz) may have a property that transmits nonmetal and nonpolar materials. Furthermore, since a resonant frequency of various kinds of molecules spreads over a terahertz band, by identifying the molecules in real-time through a nondestructive, unopened, and non-contact method, it is expected that unprecedented analytical techniques of new concept will be provided for medical care, medical science, agricultural food, environmental measurement, bio, and advanced material evaluation. Accordingly, in relation to a terahertz wave, its wide variety of applications expand rapidly. The terahertz wave does not affect the human body because of its very low energy of several meV and its demand as essential core technology for realizing human-centered ubiquitous society is drastically increased. However, techniques satisfying real-time, portable and low cost simultaneously have not developed yet.
As a terahertz generating method currently being used, there are diverse techniques such as a frequency doubling technique, a backward wave oscillator, a photomixing technique, a CO2 pumped gas laser, a quantum cascade laser, and a free electron laser. Many studies in development of a wave source operating in a frequency band of 0.1 THz to 10 THz, called a THZ gap region, are in progress but an appropriate wave source technique satisfying ultra-micro, uncooled, and high-output conditions necessary for commercialization is not mature until now. Moreover, there is no technique for turning a terahertz wave at high speed in a broad frequency band. If it is possible for a terahertz wave to vary at high speed in a broad frequency band, various physical phenomena may be monitored in real-time in a terahertz band.
A terahertz device being used most widely until now is a time domain spectroscopy device that projects a femtosecond-level ultra short pulse laser on a semiconductor-based photoconductive antenna having a high-speed response rate to generate and detect terahertz waves. The terahertz device consisting of a femtosecond-level pulse laser and a photoconductive antenna provides a high signal to noise ratio (SNR) but requires a femtosecond-level pulse laser and very accurate optical device. Therefore, in terms of price and size, there are several limitations in developing a terahertz device as a measuring instrument of a portable concept.